Flexible sear mechanism for firearms



Dec. 7, 1948. A. H. TOMPKINS FLEXIBLE SEAR MECHANISM FOR FIREARMS 4 Sheets-Sheet 1 Filed Feb. 15, 1946 INVENTOR A; amr H. 751mm: BY 9 7/M ATTORNEYS Dec; 7, 1948. A. H. T.OMPKINS FLEXIBLE SEAR MECHANISM FOR Fl EREARMS Filed Feb. 13, 1946 il l] 4 Sheets-Sheet 2 INVENTOR A; saw/Z IZMP/f/MS ATTORNEYS Dec. 7, 1948. TQMPKINS 2,455,830

FLEXIBLE SEAR MECHANISM FOR FIREARMS Filed Feb. 13, 1946 4: Sheets-Sheet 3 lN-VENTOR 2 2/ 20 37 A4 amrfiifm mm #762413 ATTORNEYS Dec. '7, 1948. A. H. ToMPKm 2,455,830

FLEXIBLE SEAR MECHANISM FOR FIREARMS Filed Feb. 13, 1946 I 4 Sheets-Sheet 4 I Patented Dec. 7, 1948 FEEXIBEE'YSEAR MECHANISM'FoR Albert H. Tompkins, Springfield,-,Mass= Application Tlii'seinvention:relatesitofirearms; and has for one; objectitha improvement: of the hammer or bolt release mechanism so as togive asteadier wiggerpull than: has:- heretofore been possible; and; tin outz'to az minimum the motion of the mggenf particularly atithelpointof release. A ohject istto' provideatrigger and sear mechanismainiswhich the strength of pull may be-l regulated easilyby an simple screw adjustmenti. A further object is to provide a" trigger and; sear? mechanism" of: greater. simplicity than formerrm'eohanismsgfl and? which is less expensive to manufaoturea Aamrther. objectis to improve the-ibreechb'locleito 1 increase greatly the strength oizithelfirearma i mfurthersobject' isltoprovide im-. pmvedxautomatiefihin'g pin retractingm'echanism operative: upomthez'. breechblockbeingopened. Additional objects will: appear from the: followits description amt claims.

The-invention will now be described withreference to the accompanying drawings, in which:

Rigs. hand:litarecollectively a side elevation qii'theaarm;r-- t Eig4J-.2-li$i?a fragmentary sidewelevationi with the brleechblock openrandiithe: hammercocked, and with; somewarts: hrokenaway to show the:.in-- terionconstruction; r a

Fig. 3 is a similar view with the breechblo'ck clbsedianimthewhammer in the. rest position to which; it returns after: firing;

Eig;.,.4,is:a, detail ofthe. sear: and hammer in mposition intermediate those'oi Figs; 2 and 3;

Fig. 52 1s.: a-iside-elevation with the breechblock closedhnartia-lly broken away; in medianv section;

Fig. firiszartop plan with the breechblockiabout tcibewonenedz; l

-..7-sh0ws:,-in-.median, section the first stage inith'eg opening ofthebreechblock;

Fig; ,8 -is,1 at side. elevation, partly broken away, qhthesame position as-in Fig; '7;

Fig. 9 is a side elevation showing the first stage int-1closlnggthe breechblock;

Fig. 1-1; istaasection on line 1'1.--11-of Fig.110; T

Fig. 112 isiasection on line 12-12 of Fig; 3; and? Figs: 13 and 14 are) modifications showing the: user of thee improved sear on two. types of: bolt n action firearms.

T-heimprovedbreechblock and sear mechanism; is. shown asapplied for illustration toa single. shot-itarget pistol, but. it. is. obvious that. various 1- featuresuof the ;mechanism i can be usedin; other settings The. mainframe l. whichflcarries thev operatingiparts ofthaarm is securediinany or. desired:- way in a stock. 2'.- This. stock.

February 13, 1946; swarm:garters 8Claims. (cmzeeat preferably extends along the barrel andlas shown in Fig; is provided: withslot. 41 to; retain a weight for giving th'e desired balance to i the arms The barrell isshownza (Fig. 2-).- as: threaded into: the frame at E and heltllby. a pinr-oriscrewt.

' mbreechblook' indicatedi generically at l is: formed 'ilrtwozmajor: pieces; .a iblock 8 and: a locking or fingerl piece 9: Thesblockxil is'ahinged at. I lit-tic: the zfram'e' adj acenttheiba'rrel so. that itican' be swungiupwardly to expose the. barrel chamber. Ai firing: pint lili is'slidable; in' a hole: [2 in the: block; at directed? soithat the a point of the firing pin will strike the primer of the cartridge; .A=xgroove l4 inathe; firing pin receiveszthe reduced-end l-5i otia set screw lli threaded into the. blocmI8,..so:-thatlthe firing: pin? may have the free'lmotion needed" for. its: operation; but cannot falliout WhEIIlthE-blBGOhblOCk isiopen.

Thetrearof; the. sidewalls. of the block; 8 are formed 1 with. a ver.tica1: slideway such: as: vertical:

7 groovesvl'l: forithe reception of aft-slot I8uin the finger: piece which in? this; way.- is made verticallysslidable. Oneiof the: ribs 20 formedby. thezgroovese l liisicuttaway atiZ I; (Figs. 6;v8, 11:-and:

1-2); tosreceive freelythelturned dowmend: 22 ofa. set screw 2 3 secured in: the finger. piece 9: I he finger piece is: thus: permitted: a; limited vertical; sliding motion relative" to; the:- block 8:; Normally, the finger piec'eris: held idown on: the same I leve1;:as5theb10ck fishy) a bentspring; 24- (Figs. 1,0-

and; l1) heldwby a; screwrzfisin-iaislot. zaformedz in: the: block and v having oneend projecting into: aire'cess '2Fl in theqfinger piece:

The: frame;v to the: rear; of the breechblock;

is; formed'with; two, verticalzsurfaoes 28 and 29:

separatedwby:whorizontaL steppiiils The frameis 1' cut" out with a central slot 3+ to receive the hammer, 32 there being. a. corresponding re'cesse .3:: in ;the;fineer piece" 9; separated on a slant line: 344mm: a narrowerl'recess 35-embracing slabbed Ofif' portions; 3610f the:firing.pinl l' just back of its head: 31;! The back Ofrthis headis cut away at; 3$oto1mateawithi the slanting, surface 34', so:

that; aswthe finger piece, is.:in raised positiomrelative to the block, the firing pin willbewithdrawn positively" from its firing: position. The hammer reoess= z3l dOESJIlOt extendstovthe :top of; the frame, leaving; a cross @bridge; 3 9-. which may serve as an abutment against: which; as shoulder Ml on the" ment surfaces 28 and 29 of the frame when the block is in its normal position of Fig. 5. For this purpose the finger piece has an upper vertical surface 4| separated by a shoulder 42 from a lower vertical surface. Referring to Fig. 5 it will be noted that the upper surface 4| is shorter than its mating surface 28 and that the lower surface 43 is shorter than its mating surface 29 so that a substantial space is left between the shoulders 35 and 42. When the breechblock is in closed position these pairs of surfaces act as abutments which transmit the force of the explosion to the frame. piece 9 is grasped and drawn upwardly. Initially both pairs of surfaces prevent any-swinging movement of the breechblock, as any swinging movement would press the abutments more tightly together on account of the position of the hinge ID. The finger piece thus moves verticallyand against its spring. When the finger piece ha moved upwardly so that surface 4! moves beyond the top of surface ZB'and surface 43 moves beyond shoulder 30 swinging movement of the breechblock is permitted and the block 8 will catch up with the finger piece on account of its spring connection. In order to avoid binding the lower pair of abutting surfaces are preferably made of slightly less height than the upper pair; as the upper surface 4| is, by reason of its horizontal alignment with pivot l0, moving almost parallel to the surface 28 at the instant of disengagement.

Locking of the breechblock is accomplished by pressing downwardly on the block 8 rather than on the finger piece which, as shown in Fig. 9, initially comes to a position against shoulder 30 where it is incapable of downward movement. The block is, however, freeto move downwardly on account of the spring connection and assumes more and more a horizontal position with the finger piece remaining elevated but tending towards the position of Fig. 7. As soon as this position is reached the lower surface 43 clears the shoulder 35 and the finger piece is shot downwardly by the spring. The breechblock is now locked and can be freed only by pulling upwardly on the finger piece. 1

The hammer 32 is pivoted to the frame at 44 and has a front pin 45 and a. rear pin 46 each extending laterally outwardly at each side. The usual spacing sleeves 41 on the pivot maintain the hammer centralized. The mainspring 48 is of hairpin shape with its loop extending around a screw 49 and between its Washer 50 and the frame. The two sides of the hairpin straddle the hammer and overlie the pins 45 and 46. Pin 45 tensions the mainspring as the hammer is drawn to cooking position and is acted on by the spring to drive the hammer into firing position upon release. Pin 46 is set to make contact with the spring on the rear side of the pivot just before the hammerreaches firing position and serves to return the hammer to a neutral position free of the firing pin.

The hammer is provided with a sear notch 5| to engage the end of the sear 52 which is in the form of a flat spring looped around a pin 53. The sear rests against a pin 54 between pin 53 and the hammer and is pressed against the hammer by a flat sear spring 55 clamped to the frame by a screw 56. To adjust the force with which the sear is held to the hammer, and thus the pull of the trigger required for release, a set screw 51 is threaded throughthe frame so as To disengage the breechblock the finger to be accessible when the breechblock is swung up (Fig. 2) and to bear against the upper surface of the sear spring. The trigger 58 is pivoted at 59 to the frame and has a forwardly projecting nose 60 adjacent which is a short fiat spring 5| held to the trigger by a screw 62. The trigger nose and the spring 6| fit together into a recessed block 53 screwed or riveted to the sear, the spring 6| acting merelyftoprevent any lost motion between the scar and trigger.

The cocked position of the parts is shown in Fig. 2. The sear is pressed into the sear notch by the spring 55 but is otherwise unstressed. As

' the trigger is drawn back the portion of the sear between pins 53 and 54 is fixed downwardly against, of course, progressively increasing resistance. The flexing of this part of the sear gives to the portion between pin 54 and the hammer a tendency to bend upwardly which is resisted both by its engagement with the sear notch and by the sear spring 55. 1 This flexing of the sear is accomplished. withsuch slight, movement of the trigger as to be practically im-J perceptible, the feelbeing thatwof increasing pressure rather than, movement. This, is par-. ticularly noticeable when the sear finally springs; free of the sear notch; since the motion is prace tically confined to the end portion of. the searbeyond pin 54 and is not apparent at'the trig-. ger. There being no jumping of..the.trigger-at' the instant of firing, muchgreater accuracy is: possible as has been shown by:the use by experts of a target pistol constructed as above.v

The sear mechanism is equally adapted to other types of arm. Figs. 13 and 14 show its use on two.- types of bolt action in which the respective sears 64 and 65 are flexed upwardlyv between pins 66: and 61 and rest pins 63 and 69; In Fig.-1'3- a rocker i0 is interposed between thetrigge'r H and the sear, while in Fig. 14 the triggeri 12 is provided with a heel 73 on the rear side of the trigger pivot. In both cases the triggerwhen pulled causes the sear to be flexed -upwardly," pulling its free end downwardly to release 'the bolt 74 or 15. Other adaptations to specific types of bolt 0r hammer actions will 'readily suggest themselves from the above? description.

I. claim: '1 v 1 1. In a firearm, a firing member provided with a sear engaging abutment, a springactuating said firing member, a flexible sear pivoted-atone end, its second end engaging said *abutmentto hold said member against actuation Icy-said spring, a second abutment positionedinterm'e diate the ends of the scar and engaging-that side of the sear which faces the firing member, a trigger and trigger operated means for flexing the sear between its pivot and said secondabiitment in a direction to flex its second erid'out'of engagement with the abutment on the firing member. J

2. In a firearm, a firing member provided with" a sear engaging abutment, a spring actuating said firing member, a flexible sear pivoted at one end, its second end engaging said abutment tohold said member against actuation by said spring, a secondabutment positioned intermediate the ends of the sear and engaging tliat 'side "of the sear which faces the firing memberja spring engaging the sear adjacent its second end 'tdpress the latter against said firing member,*'a trigger;- and trigger operatedmeans for flexing the sear between its pivot and said seconda-butment direction to flex its second end but of engagef j ment with the abutment on the firing member;

3. In a firearm, a firing member provides with a scar engaging abutment, a spring actuating said firing member, a flexible sear pivoted at one end, its second end engaging said abutment to hold said member against actuation by said spring, a second abutment positioned intermediate the ends of the sear and engaging that side of the sear which faces the firing member, a spring engaging the opposite side of the sear adjacent its second end to press the latter against the firing member, means for adjusting the tension of the last named spring, a trigger and trigged operated means for flexing the sear between its pivot and said second abutment in a direction to flex its second end out of engagement with the abutment on the firing member.

4. In a firearm having a pivoted hammer having a scar notch, a spring stressing the hammer for movement toward firing position, a flexible sear pivoted at one end and at its other end engaging the sear notch to hold the hammer in cocked position, an abutment engaging the sear intermediate its ends to prevent its movement in a direction toward the hammer, a trigger and trigger operated means for flexing the sear between its pivot and theabutment in a direction to flex its second end out of engagement with the sear notch.

5. In a firearm having a pivoted hammer hav ing a sear notch, a spring stressing the hammer for movement toward firing position, a fiexible' sear pivoted at one end and at its other end engaging the sear notch to hold the hammer in cocked position, an abutment engaging the sear intermediate its ends to prevent its movement in a direction toward the hammer, a spring engaging the second end of the sear to press it into the sear notch, a trigger and trigger operated means for flexing the sear between its pivot and the abutment in a direction to flex its second end out of engagement with the sear notch.

6. In a firearm having a pivoted hammer having a sear notch, a spring stressing the hammer for movement toward firing position, a flexible sear pivoted at one end and. at its other end engaging the sear notch to hold the hammer in cocked position, an abutment engaging the sear intermediate its ends to prevent its movement in a direction toward the hammer, a spring engaging the second end of the sear to press it into the sear notch, means for adjusting the tension of the last named spring, a trigger and trigger operated means for flexing the sear between its pivot and the abutment in a direction to flex its second end out of engagement with the sear notch.

7. In a firearm having a pivoted hammer having a sear notch, a spring stressing the hammer for movement toward firing position, a flexible sear pivoted at one end and at its other end engaging the sear notch to hold the hammer in cocked position, an abutment engaging the sear intermediate its ends to prevent its movement in a direction toward the hammer, a fiat spring secured at one end and engaging the second end of the sear to press it into the sear notch, a trigger and trigger operated means for flexing the sear between its pivot and the abutment in a direction to flex its second end out of engagement with the sear notch.

8. In a firearm having a pivoted hammer having a sear notch, a spring stressing the hammer for movement toward firing position, a flexible sear pivoted at one end and at its other end engaging the sear notch to hold. the hammer in cocked position, an abutment engaging the sear intermediate its ends to prevent its movement in a direction toward the hammer, a flat spring secured at one end and engaging the second end of the sear to press it into the sear notch, a screw adjustably engaging said flat spring intermediate its ends to regulate its pressure against the sear, a trigger and trigger operated means for flexing the sear between its pivot and the abutment in a direction to flex its second end out of engagement with the sear notch.

ALBERT H. TONIPKINS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 101,418 Berdan April 5, 1870 378,091 Greth Feb. 21, 1888 1,858,601 Sedgley May 17, 1932 2,331,405 Loomis Oct. 12, 1943 2,399,253 Reill Apr. 30, 1946 FOREIGN PATENTS Number Country Date 639,493 France Mar. 10, 1928 

